HP UX SNAplus2 manual LEN Nodes

SNA Terms and Concepts

Basic APPN Concepts

An APPN end node can be attached to multiple network nodes (see EN3 in Figure 1-4, “Portion of a Sample APPN Network,”) but it can have CP-CP sessions active with only one network node at a time—its network node server. The other network nodes can be used only to provide intermediate routing for the end node or as substitute network node servers if the main network node server becomes unavailable.

An APPN end node can also have a direct link to another APPN end node or a LEN node, but CP-CP sessions are never established between two end nodes.

LEN Nodes

A low-entry networking node (LEN node) is a type 2.1 node that uses independent LU 6.2 protocols, but does not support CP-CP sessions. It can be connected to an APPN network node or end node, but does not support APPN functions.

An APPN network node can provide routing services for an attached LEN node, enabling the LEN node to participate in an APPN network without requiring link stations to be defined between the LEN node and all of the nodes in the APPN network.

LUs in the APPN network with which the LEN node may want to establish sessions must be defined to the LEN node as if they reside on the LEN node's network node server. The LEN node establishes sessions with LUs on its network node server. The network node routes the session through the APPN network to the node in the network where the LU actually resides. LUs on the LEN node must be predefined to the network node that serves the LEN node. LU resources on LEN nodes (unlike those on end nodes) cannot be registered on the network node server.

An APPN end node cannot provide intermediate routing. When a LEN node's only link is to an APPN end node, the LEN node can communicate only with LUs on the end node through the direct link between the two nodes.

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